Phosphorus-doped Carbon Nitride Research Articles

Phosphorus-doped carbon nitride for enhanced supercapacitor performance and energy storage applications

Exploiting the advantages of graphitic carbon nitride doped with phosphorus (xP-CN) electrodes were designed for high-performance hybrid asymmetric supercapacitor via facile hydrothermal and thermal decomposition techniques. The structural, surface chemistry, functional and morphological characterizations evidence depict successful phosphorus incorporation in Carbon Nitride (CN). X-ray photoelectron spectroscopy analysis shows that phosphorus (P) atoms have replaced corner carbon atoms in the CN structure. These findings clearly demonstrate that the presence of phosphorus doping improves the electrochemical activity of the electrodes. The designed three-electrode system has a specific capacitance of 189.36 F/g with a current density of 1 A/g. Phosphorus doping has been discovered to play a significant role in improving both specific capacitance and cycling stability. The capacitance retention of the two-electrode solid-state device has 97.2 % after 5000 cycles. These electrochemical evaluations reveal that the xP-CN electrode exhibits superior electrochemical performances than pristine CN. This doping strategy for CN presents a novel and efficient approach for crafting high-performance supercapacitors.

Metal-Free Carbon Co-Catalysts for Up-Conversion Photo-Induced Catalytic Cancer Therapy.

Near-infrared (NIR)-responsive metal-free carbon co-catalysts that convert glucose into H2O2 to generate reactive oxygen species (ROS) are developed from phosphorus-doped carbon nitride (P-C3N4) and graphene quantum dots (GQD) composites, for enhanced photocatalytic cancer therapy by light exposure in the targeted tumor microenvironment. Upon irradiation, the NIR light is converted by GQD with up-conversion function into visible light to excite P-C3N4 for photocatalytic conversion of glucose into H2O2, which subsequently decomposes into ROS. ROS thus generated exhibits an excellent anticancer efficacy for efficient cancer therapy with minimal side effects, as evidenced by both in vitro and in vivo studies. This study demonstrates, for the first time, a cancer therapeutic of GQD/P-C3N4 composite that utilizes a two-step cascade effect using initially NIR-triggered GQD nanoparticles to activate P-C3N4 to photocatalytically generate ROS for effective and targeted cancer therapy.

CoO quantum dots anchored on P-doped carbon nitride improves peroxymonosulfate activation to degrade sulfamethoxazole

The development of highly dispersed and ultra-small size cobalt-loaded catalysts is crucial for achieving efficient and low secondary pollution in peroxymonosulfate (PMS) activation processes. Herein, a phosphorus-doped carbon nitride (PCN) loaded with CoO quantum dot catalyst (Co80-PCN) was derived from the mixture of BINAP-CoCl2 complex (BINAP = 1,1′-binaphthyl-2,2′-diphosphine) and carbon nitride (CN). Structural studies revealed that cobalt oxide quantum dots with an average diameter of 9.99 nm were evenly and securely attached to the PCN substrate. The optimal Co80-PCN/PMS system demonstrated an almost 100% degradation efficiency of sulfamethoxazole (SMX, 10 mg/L) within 15 min, with a reaction rate constant of 0.3341 min−1, which was 30.1 times higher than that of the CN/PMS system. This outstanding degradation performance could be primarily attributed to the enhanced catalytic activity of CoO quantum dots and the improved electronic structure resulting from P-doped CN. This work offers valuable insights for the future design of carbon material loaded quantum dot catalysts.

Photocatalytic CO2 reduction integrated with biomass selective oxidation via single-atom Ru and P dual sites on carbon nitride

Photocatalytic biorefinery integrated with CO2 reduction to co-produce value-added chemicals and fuels is significant but challenging. Herein, a novel photocatalyst with dual active sites is constructed, in which Ru single atoms coordinated with N2O2 on phosphorus-doped carbon nitride (Ru1N2O2@PCNx) via a pre-assembled pyrolysis strategy. Ru1N2O2@PCN1.0 catalyst exhibits an exceptional performance in both CO2 reduction and biorefinery processes, originating from the high photon-to-electron conversion rate. It achieves an extraordinary CO2 reduction and biorefinery, with 100.1 μmol g−1 h−1 evolution of CO and 91.2% yield of lactic acid. Furthermore, the as-prepared Ru1N2O2@PCN1.0 is successfully used in biomass-derived monosaccharides and xylan systems, validating the universality for broad applications. Experimental and theoretical analysis indicates that doping P in CN by replacing a corner C atom facilitates charge transfer/separation. Additionally, the introduction of Ru-N2O2 coordination regulates the electronic structure of CN and reduces the reaction energy barrier.

Phosphorus doping to enhance the peroxymonosulfate activation efficiency of carbon nitride for degrading tetracycline

Herein, a new type of peroxymonosulfate (PMS) activator—phosphorus-doped carbon nitride (P-C3N4)—was prepared using a one-step thermal shrinkage method. Material characterisation confirmed the successful doping of phosphorus in graphite-phase carbon nitride (g-C3N4) by replacing the carbon atoms in its triazine ring structure to form PN bonds. Phosphorus doping can regulate and re-organise the surface electronic structure of g-C3N4 without changing its structure. Moreover, phosphorus doping promotes varying degrees of optimisation of the g-C3N4 pore structure and electronic transport between the g-C3N4 sites. Batch experiments on tetracycline (TC) degradation revealed that 0.2 P-C3N4 showed the best physicochemical properties, the constructed P-C3N4/PMS system exhibited high TC removal efficiency and P-C3N4 exhibited good reusability and structural stability. Quenching experiments and electron paramagnetic resonance tests revealed that singlet oxygen was the primary active species in the P-C3N4/PMS system. The mechanism of PMS activation using P-C3N4 was then proposed. The analysis of TC and its intermediate products using liquid chromatography–mass spectroscopy demonstrated that TC was primarily degraded via ring-opening, hydroxylation, deamination and dealkylation reactions. Analysis using the toxicity estimation software tool demonstrated that most intermediate products were less toxic than TC. Thus, this study provides a feasible method for removing TC from aquatic environments.

A dual-lithiophilic interfacial layer with intensified Lewis basicity and orbital hybridization for high-performance lithium metal batteries

Controlling Li nucleation and growth by an interfacial layer is one of the critical challenges to achieving practical lithium metal batteries. In this work, we present a dual-lithiophilic interlayer, which has affinity to both Li + and Li 0 with the concept of intensified Lewis basicity and orbital hybridization. It was achieved by phosphorus-doped carbon nitride (PCN) layers in contact with Li metal electrode. Spectroscopic and electrochemical analyses demonstrated that strong interaction between the Li + and PCN facilitates the charge transfer process. Driven by the orbital hybridization, under the PCN interfacial layer Li deposits grow with a planar morphology, mitigating electrolyte decomposition. A Li/Li symmetric cell employing the PCN interfacial layer operated for more than 400 cycles at 2 mA cm –2 and 2 mAh cm –2 . Furthermore, a Li/NCM811 pouch cell with the PCN interfacial layer stably operated with 70% capacity retention for 330 cycles under practical operating conditions.

Phosphorus-doped oligomeric carbon nitride for selective fluorescence detection of mercury (II) ions

Selective and sensitive analysis of mercury (II) ions is a challenging topic in fluorescent sensors. Herein, we obtained a new selective mercury (II) ion fluorescence sensor by converting microscale hollow-tube-structured phosphorus-doped polymeric carbon nitride into phosphorus-doped carbon nitride oligomers with needle-like nanostructures by a hydrothermal reaction. The unique oligomeric microstructure and surface-rich terminal amino and hydroxyl functional groups of the fluorescence sensor synergistically endow it with selective quenching of mercury (II) ions. This phosphor-doped carbon nitride oligomer-based mercury (II) ion-selective fluorescence sensor achieves a minimum detection limit of 0.35 nmol L−1 in the range from 1–100 nmol L−1 (correlation coefficient of 0.9976) and a quantum yield of 16.6%. The detection of mercury (II) ions in actual shrimp samples demonstrated the sensitivity and accuracy of this fluorescence sensor. This work provides a new possibility for developing green and inexpensive mercury (II) ion-selective fluorescent sensors.

Phosphorus Tailors the d-Band Center of Copper Atomic Sites for Efficient CO2 Photoreduction under Visible-Light Irradiation.

Photoreduction of CO2 into solar fuels has received great interest, but suffers from low catalytic efficiency and poor selectivity. Herein, two single-Cu-atom catalysts with unique Cu configurations in phosphorus-doped carbon nitride (PCN), namely, Cu1 N3 @PCN and Cu1 P3 @PCN were fabricated via selective phosphidation, and tested in visible light-driven CO2 reduction by H2 O without sacrificial agents. Cu1 N3 @PCN was exclusively active for CO production with a rate of 49.8 μmolCO gcat -1 h-1 , outperforming most polymeric carbon nitride (C3 N4 ) based catalysts, while Cu1 P3 @PCN preferably yielded H2 . Experimental and theoretical analysis suggested that doping P in C3 N4 by replacing a corner C atom upshifted the d-band center of Cu in Cu1 N3 @PCN close to the Fermi level, which boosted the adsorption and activation of CO2 on Cu1 N3 , making Cu1 N3 @PCN efficiently convert CO2 to CO. In contrast, Cu1 P3 @PCN with a much lower Cu 3d electron energy exhibited negligible CO2 adsorption, thereby preferring H2 formation via photocatalytic H2 O splitting.

Phosphorus Tailors thed‐Band Center of Copper Atomic Sites for Efficient CO2Photoreduction under Visible‐Light Irradiation

AbstractPhotoreduction of CO2into solar fuels has received great interest, but suffers from low catalytic efficiency and poor selectivity. Herein, two single‐Cu‐atom catalysts with unique Cu configurations in phosphorus‐doped carbon nitride (PCN), namely, Cu1N3@PCN and Cu1P3@PCN were fabricated via selective phosphidation, and tested in visible light‐driven CO2reduction by H2O without sacrificial agents. Cu1N3@PCN was exclusively active for CO production with a rate of 49.8 μmolCO gcat−1 h−1, outperforming most polymeric carbon nitride (C3N4) based catalysts, while Cu1P3@PCN preferably yielded H2. Experimental and theoretical analysis suggested that doping P in C3N4by replacing a corner C atom upshifted thed‐band center of Cu in Cu1N3@PCN close to the Fermi level, which boosted the adsorption and activation of CO2on Cu1N3, making Cu1N3@PCN efficiently convert CO2to CO. In contrast, Cu1P3@PCN with a much lower Cu3delectron energy exhibited negligible CO2adsorption, thereby preferring H2formation via photocatalytic H2O splitting.

Adsorption coupling photocatalytic removal of gaseous n-hexane by phosphorus-doped g-C3N4/TiO2/Zn(OAc)2-ACF composites.

VOCs emission reduction in the petroleum and petrochemical industry is a hot and difficult topic at present. The single method may not be able to meet the actual treatment status. Therefore, the adsorption coupled photocatalytic degradation technology was used to remove VOCs. Phosphorus-doped carbon nitride (PCN) and PCN/TiO2 were prepared by hydrothermal synthesis and sol-gel method, and then PCN/TiO2/Zn(OAc)2-ACF composites were prepared by ultrasonic impregnation on zinc acetate modified activated carbon fibers (Zn(OAc)2-ACF). The removal efficiency of n-hexane by composite materials was explored in a self-made reactor, and the factors affecting removal efficiency, removal mechanism, and possible ways of degradation were investigated. The results showed that under the optimum reaction conditions (initial concentration of n-hexane 200mg/m3, space velocity 1000h-1, light intensity 24W, mass fraction of doped PCN 6%, loading twice, calcination temperature 450°C), PCN/TiO2/Zn(OAc)2-ACF composite has the highest removal efficiency of n-hexane (90.2%). The adsorption capacity of the composites after doping the P element was 215.3mg/g, which did not enhance the adsorption performance compared with that before doping, but the removal rate of n-hexane was higher. This showed that doping P element was helpful to enhance the photocatalytic activity of the composites.

Self-Poisoning by C2 Products in CO2 Photoreduction Using a Phosphorus-Doped Carbon Nitride with Nitrogen Vacancies

Self-Poisoning by C₂ Products in CO₂ Photoreduction Using a Phosphorus-Doped Carbon Nitride with Nitrogen Vacancies

Phosphorus doped carbon nitride with rich nitrogen vacancy to enhance the electrocatalytic activity for nitrogen reduction reaction

It is very significant to explore the metal-free electrocatalyst with high activity and good stability for Nitrogen reduction reaction (NRR). Herein, an efficient and stable metal-free NRR electrocatalyst P-NV-C3N4 is synthesized successfully through the P doping in C3N4 combined with the design of nitrogen vacancy (NV) structure. The electrocatalyst has excellent electrocatalytic activity, selectivity and stability (over 20 h) for NRR in neutral electrolyte. Its yield of NH3 is 28.67 μg h−1 mgcat.−1, and the FEs is 22.15% at −0.3 V (vs. RHE), which is considerably better than pristine C3N4, P-C3N4 and NV-C3N4. Structural characterization and Density functional theory calculation (DFT) reveals that P doping can effectively promote water splitting and provide hydrogen source for nitrogen reduction. Meanwhile, the N-vacancy structure can significantly inhibit the formation of HER pathway, hinder the Heyrovsky step (H*→H2), and promote the adsorption and activation of N2. Through the research of different NRR pathway, its optimal reaction pathway (distal pathway) is determined. In addition, P-NV-C3N4 can reduce the energy barrier of potential-determining step (ΔGPDS) in NRR process, and stabilize the reaction intermediates, thus improving its NRR performance.

Photocatalytic degradation of tetracycline by Phosphorus-doped carbon nitride tube combined with peroxydisulfate under visible light irradiation.

Photocatalysis has been regarded as a kind of environmentally friendly advanced oxidation process to eliminate pollutants. In this work, Phosphorus-doped carbon nitride tube (PCN) was synthesized via a hydrothermal calcination method and applied to degrade tetracycline (TC) through combing with peroxydisulfate (PDS) under visible light irradiation. Experimental results showed that the optimized catalysts PCN-5 exhibited superior degradation performance and reusability for TC degradation. 96.4% TC could be degraded for optimal PCN-5 with 0.3 g·L-1 catalysts and 1.0 g·L-1 PDS under visible light within 60 min. In addition, the degradation rate constant for TC of PCN + PDS + Vis system was still above 85% after five uses. Radical trapping experiment indicating that O2·- is the dominant radical for TC degradation. The findings of this work revealed the potential application of the PCN + PDS + Vis system toward degrading contaminants in wastewater.

A phosphorus-doped g-C3N4 nanosheets as an efficient and sensitive fluorescent probe for Fe3+ detection

The phosphorus-doped carbon nitride nanosheets (P-g-C3N4 nanosheets) were prepared by ultrasonic stripping. Through the performance characterization, it was found that the P-g-C3N4 nanosheets emitted pure blue light with stable performance. Compared with other metal ions, it was found that the quenching reaction between P-g-C3N4 nanosheets and Fe3+ was the strongest. The detection limit of Fe3+ was found to be about 1.63 μM. P-doped g-C3N4 is expected to be an efficient fluorescent probe for Fe3+ detection.

Photocatalytic degradation of dinotefuran by layered phosphorus-doped carbon nitride and its mechanism

It is well known that the widespread residue of the neonicotinoids dinotefuran in aquatic environment has adverse effects on non-target organisms. Therefore, the efficient removal of dinotefuran in water environment is an important measure to control its safety risk. In the present study, layered phosphorus-doped carbon nitride (HPCN0.5) was prepared via a simple hydrothermal method and applied for photocatalytic degradation of dinotefuran. With the addition of phosphorous acid, a tube-like structure was observed in HPCN0.5 and planar sheets were stacked inside the tubes. Compared to bulk g-C3N4, the degradation efficiency of dinotefuran was 6 times higher. According to the reaction mechanism and product identification analysis, the main photodegradation pathways correspond to demethylation and hydroxylation. The result of the acute toxicity test revealed the toxicity of dinotefuran to earthworm was greatly reduced after photodegradation by HPCN0.5. In addition, HPCN0.5 was capable of simultaneously removing three other commonly used neonicotinoids. This work proved that HPCN0.5 has great potential to be applied in alleviating negative effects of neonicotinoids on the non-target organisms and environment.

Phosphorus-doped Carbon Nitride Nanosheets as Efficient White-LED-Light-Driven Photocatalyst for Hydrogen Evolution and Tetracycline Degradation

g-C3N4 has received much attention due to its role in photocatalytic hydrogen evolution and contaminants degradation. Nevertheless, the photocatalytic property of bulk g-C3N4 (BCN) is seriously restricted owing to its short photo-generated carrier lifetime, small specific surface area and low visible light utilization rate, etc. In this study, nanosheet constructing and heteroatom phosphorus (P) doping, as two important strategies, are synergistically adopted to co-enhance its activity. The controllable P atoms were successfully doped into the framework of g-C3N4 nanosheet (NCN-P) through forming P-N bond. The optimized NCN-P sample displays an excellent H2 production rate (3263.99 µmol·g−1·h−1) under white LED light irradiation, which is more than 11.6 times that of the BCN. Moreover, it also exhibits excellent photocatalytic degradation ratio of tetracycline reached 80% in 1 h. Furthermore, the optimized NCN-P sample still maintains robust photocatalytic performance after recycling tests, making it as a bright prospect photocatalyst for solar energy utilization and contaminants removal.

Phosphorus-doped carbon nitride with grafted sulfonic acid groups for efficient photocatalytic synthesis of xylonic acid

The photocatalytic selective oxidation of biomass-derived feedstocks to high-value organic acids is promising and challenging, especially for the production of xylonic acid.

P- and F-co-doped Carbon Nitride Nanocatalysts for Photocatalytic CO2 Reduction and Thermocatalytic Furanics Synthesis from Sugars.

A new P- and F-co-doped amorphous carbon nitride (PFCN) has been synthesized via sol-gel-mediated thermal condensation of dicyandiamide. Such synthesized P- and F-co-doped carbon nitride displayed a well-defined mesoporous nanostructure and enhanced visible light absorption region up to infrared with higher BET surface area of 260.93 m2 g-1 ; the highest recorded value for phosphorus-doped carbon nitride materials. Moreover, the formation mechanism is delineated and the role of templates was found to be essential not only in increasing the surface area but also in facilitating the co-doping of P and F atoms. Co-doping helped to narrow the optical band gap to 1.8 eV, thus enabling an excellent photocatalytic activity for the aqueous reduction of carbon dioxide into methanol under visible-light irradiation, which is fifteen times higher (119.56 μmol g-1 h-1 ) than the bare carbon nitride. P doping introduced Brønsted acidity into the material, turning it into an acid-base bifunctional catalyst. Consequently, the material was also investigated for the thermal conversion of common carbohydrates into furanics.

In situ growth of CdS quantum dots on phosphorus-doped carbon nitride hollow tubes as active 0D/1D heterostructures for photocatalytic hydrogen evolution

CdS quantum dots (QDs) were decorated onto phosphorus-doped hexagonal g-C3N4 tube (P-CNT) to form a novel high-preformance photocatalyst (CdS QDs/P-CNT) via an in-situ oil bath approach. The ultra-small CdS QDs with the average diameter of ~9 nm are homogeneously anchored on the both external and internal surface of P-CNT hollow channel (~25 μm), yielding a type of zero-dimensional (0D)/one-dimensional (1D) heterojunction. The CdS QDs/P-CNT-1 exhibits the maximum photocatalytic H2 evolution rate of 1579 μmol h−1 g−1 under visible-light irradiation, which is 31.6, 6.8, 4.7 and 3.1 times higher than P-CNT, CdS, CdS/BCN and CdS/CNT, respectively. The improved photocatalytic activity of CdS QDs/P-CNT is primarily attributed to large surface area, P doping and formed 0D/1D heterojunction, which can broaden the light absorption, narrow the band gap, activate the H2O molecule and promote the spatial charge separation. Moreover, the DFT calculation coupled with experiment (Mott-Schottky curves) illustrates the electron transfer behavior of CdS QDs/P-CNT, showing that the Cd-1 site should be the main active center and P doping is beneficial to increase H2 production. This work provides a new strategy to design of highly active 0D/1D photocatalyst for photocatalytic H2 production.

Bridging metal-ion induced vertical growth of MoS2 and overall fast electron transfer in (C,P)3N4-M (Ni2+, Co2+)-MoS2 electrocatalyst for efficient hydrogen evolution reaction

Highly dispersed molybdenum disulfide (MoS2) nanosheets are perpendicularly grown on the phosphorus-doped carbon nitride ((C,P)3N4) nanolayers assisted with nickel and cobalt as metal-ion bridges in order to form high-quality (C,P)3N4-M (Ni2+, Co2+)-MoS2 electrocatalysts for efficient hydrogen evolution reaction (HER). Our research demonstrates that nickel and cobalt ions assisted growth could remarkably expose more active sites as a result of less layers of MoS2 and enhance the charge transfer efficiency for the well-knit and short-distance charge transfer channels between (C,P)3N4 and MoS2. In addition, P dopants make the semiconducting basal plane of carbon nitride conductive, which is critical to forming an overall fast electron transfer tunnel. Benefiting from the vertical structure and holistic charge transfer tunnels' modulation, the (C,P)3N4-M (Ni2+, Co2+)-MoS2 electrocatalysts exhibit preferable catalysis toward HER in acid medium, evidenced by the lower overpotential and smaller Rct compared to those without metal-ion bridge between them. This strategy of forging metal-ion bridges provides avenues for modifying the intrinsic catalytic activity of electrocatalysts towards HER and other energy-related processes.